import java.util.List;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 17655
 * Date: 2024-11-25
 * Time: 16:12
 */
public class test1 {
    /*
    NewCoder BM6 判断链表是否有环
     */
    public boolean hasCycle(ListNode head) {
        if(head ==null || head.next==null){
            return false;
        }
        ListNode slow = head;
        ListNode fast = head;
        while(fast !=null && fast.next !=null){
            slow = slow.next;
            fast = fast.next.next;
            if(slow==fast){
                return true;
            }
        }
        return false;
    }

    class ListNode{
        int val;
        ListNode next;
        ListNode (int x){
            val  =x;
            next = null;
        }
    }
}
